Safety cannula

ABSTRACT

A coupling system for transferring fluids from a medicament-containing cartridge to an injection site comprises a fluid flow channel, a blunt cannula defining the distal end of the fluid flow channel, a needle cannula defining the proximal end of the fluid flow channel, and means for fixedly connecting the needle cannula to the blunt cannula.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to coupling systems for transferring materialsfrom one flow conduit to another.

2. Description of the Prior Art

Disposable medicament-containing cartridge-needle units for use inconjunction with reusable hypodermic syringe holders are well known inthe art. Such cartridges conventionally feature a cylindrical bodyclosed at the proximal end with a flexible piston slidable within thebore of the cartridge and closed at the distal necked-down end with adiaphragm secured to the cartridge by a crimped-on metal collar. Thenecked-down distal end conventionally is fitted with a steelneedle/needle hub unit and a needle sheath. Such needle/needle hub unitshave, minimally, a sharp end, typical of the type associated withhypodermic syringes.

Such cartridge-needle units can be used in conjunction with reusablesyringe holders which allow the user to avoid handling thecartridge-needle unit when the needle is exposed. Nevertheless, healthcare workers are especially susceptible to accidental and potentiallyinfectious, and indeed, on occasion, possibly fatal, needle strikes dueto the careless handling and/or disposing of the cartridge-needle unitafter use. The consequences to health care workers of strikes fromneedles contaminated with various infectious diseases such as hepatitisor AIDS can be particularly severe. The frequency of such accidentalneedle strikes in the United States is surprisingly great, and has beenestimated to be approximately one million needle strikes per year.Moreover, the cost to health care organizations for the testing ofhealth care workers accidentally stricken by used needles is asignificant burden on health care costs. Therefore, it would bedesirable to further protect health care workers by providing medicamentcontaining cartridges without having to expose the user to the needlecommonly associated with such cartridges.

In response to the "accidental needle strike" situation, numerousdevices have been developed which typically shield or cover the sharpneedle tip. One recently developed system, as described inPCT/US89/00273, comprises a pre-slit injection site specificallydesigned to receive a blunt cannula. Commercially available under theInterLink trademark, this pre-slit injection site and blunt cannula havebeen adapted for intravenous administration as described in pending U.S.and foreign patent applications. One of the key features of this systemis the elimination of traditional "sharp" needles which are used innumerous procedures. For example, as described in PCT/US90/01350, theblunt cannula device is depicted in a press-fit combination with asyringe of known construction. Rather than using a traditional needle,the blunt cannula device is attached to the syringe and then insertedthrough the pre-slit injection site located in an IV tubing line. Thecontent of the syringe is then delivered into the IV line. Once thecontent is delivered, the cannula is withdrawn from the site andproperly disposed. Hence, the administration of the syringe content,through an IV line, can now be completed without the use of a standardneedle.

Hence, it would be highly desirable to provide conventional disposablemedicament cartridges adaptable to such blunt cannulae and useable withsuch pre-slit injection sites.

SUMMARY OF THE INVENTION

In accordance with this invention, an improved coupling system isprovided for transferring fluids from a medicament-containing cartridgeto an injection site which reduces the possibility of accidental needlestrikes.

More specifically, this invention provides an improved coupling systemfor transferring fluids from a medicament-containing cartridge to apre-slit injection site, the coupling system comprising a fluid flowchannel, a blunt cannula defining the distal end of the fluid flowchannel, a needle cannula defining the proximal end of the fluid flowchannel, and means for fixedly connecting the needle cannula to theblunt cannula. In a preferred embodiment, the coupling system includes ahub comprising the blunt cannula and a sleeve portion which extendsaround and beyond the proximal end of the needle cannula.

It is an advantageous feature of this invention that an improvedcoupling system is provided for commercially availablemedicament-containing cartridges which can be used safely andeffectively without exposing the user to the needle cannula. Thisreduces the susceptibility of health care workers to accidental needlestrikes.

It is another advantageous feature of this invention that a safetycoupling device is provided that may not be subject to a potentiallylengthy approval process before the U.S. Food and Drug Administration.

Other advantages will become readily apparent upon reference to thefollowing description of preferred embodiments when read in light of theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded cross-section showing a preferred embodiment ofthe coupling system of this invention.

FIG. 2 is a cross-section showing a coupling system of this invention inan assembled relation and a pre-slit injection site.

FIG. 3 shows in cross-section a coupling system of this invention incombination with a conventional medication-containing cartridge.

FIG. 4 is an exploded view of a syringe holder which can be used inconjunction with the coupling system-cartridge combination of thisinvention.

DESCRIPTION OF PREFERRED EMBODIMENTS

While this invention is described hereinafter particularly with respectto a preferred embodiment, i.e., a coupling system for transferringfluids from a medicament-containing cartridge to a pre-slit injectionsite, it also finds utility in other coupling systems for transferringfluid materials from one flow conduit to another.

With reference to the drawings, a coupling system of this invention,represented by 10, is intended for use in combination with aconventional disposable medicament-containing cartridge. The couplingsystem includes a fluid flow channel, having a proximal end 12 and adistal end 14, a blunt cannula 16 defining the distal end of the fluidflow channel, a needle cannula 18 defining the proximal end of the fluidflow channel, and means described hereinafter for fixedly connecting theneedle cannula to the blunt cannula.

In a preferred embodiment, the coupling system comprises a hub 20comprising the blunt cannula 16 defining the distal end of the fluidflow channel and a sleeve portion 22 which extends around and beyond theproximal end of the needle cannula when assembled. It is possible toassemble the coupling system at the manufacturer's site, therebyvirtually eliminating user exposure to needle cannula 12.

Needle cannula 12 can be a single or double sharp ended needle cannulaof the type commonly associated with hypodermic syringes. A needlecannula of the single ended type, as shown in FIG. 1, is preferred. Theneedle cannula preferably is fabricated of stainless steel.

For use with conventional cartridges, e.g., commercially availableCarpuject™ sterile cartridges, the radius r of sleeve 22 is about 5 mmand the distance x between the end of sleeve 22 and the proximal end ofneedle cannula 18 preferably is at least about 2 mm, more preferably 3mm, so that the proximal end of the needle cannula is adequatelyshielded when the coupling system is not attached to the cartridge. Thedistal end of the needle cannula 18 can be flush with the distal end ofthe blunt cannula. However, to reduce the undesirable possibility of theneedle cannula extending beyond the distal end of the blunt cannula dueto manufacturing tolerances, a clearance Y of at least about 0.5 mm, andpreferably, of about 1 mm can be provided.

Blunt cannula 16 is tapered at its distal end to engage an injectionsite. The blunt cannula 16 preferably is an integral part of hub 20. Thespecifics of the design of the tapered blunt cannula end portion of hub20 can be ascertained with reference to PCT/US89/000273, PCT/US90/01350,and other pending applications, the disclosures of which are herebyincorporated by reference, which describe tapered blunt cannulae for usewith pre-slit injection sites.

Various means can be employed for fixedly connecting the needle cannulato the blunt cannula and/or the hub comprising the blunt cannula Forexample, the fluid flow path inside the blunt cannula can be taperedsuch that the needle cannula can be inserted into and adhesivelyconnected to the blunt cannula. Suitable adhesives include, e.g., anepoxy based resin, and can be applied to the outside surface of theneedle cannula prior to insertion into the hub. Alternatively, theneedle cannula can be inserted into the blunt cannula or hub and theblunt cannula or hub can be melted or welded to connect the needlecannula to the blunt cannula. In another embodiment, the connectingmeans can take the form of an insert 24 which can be sized to fitthrough sleeve 22 and snap into mating portion 26 in the middle sectionof hub 20.

A removable cover sheath 28 can be provided to surround blunt cannula 16during storage and handling to preserve the sterility of the cannula.Cover sheath 28 can be snapped into engagement with the hub to surroundand protect the outwardly projecting distal end of blunt cannula 16.

Disposable medication cartridge 30 is of a conventional design andincludes a hollow, transparent body which is prefilled with a supply offluid medication or the like. Such cartridges currently are inwidespread commercial use. Cartridge 30 includes a head 32 and acylindrical body 34 which are coextensively joined together at arelatively narrow neck 36. A metallic end cap 38 covers a sealeddiaphragm 40 which extends across cartridge 30 to prevent contaminationand leakage of the fluid contents. A piston 42 is sized to be receivedin and slidable axially and reciprocally through the interior ofcartridge 30. Piston 42 is formed from a relatively dense resilientmaterial, e.g., rubber, and can be moved distally through cartridge 30for expulsing the fluid contents of the cartridge via the needle cannula18. A screw-threaded rod 44 can be connected to the piston 42 so as toproject outwardly from the end of piston 42. Screw-threaded rod 44 canbe mated to a screw-threaded piston stem of an associated holder tocomplete a piston assembly for controlling the movement of piston 42through the interior of cartridge 30. It is contemplated that othermeans known in the art can be employed for attaching the rod to thepiston stem.

The above-described medicament-containing cartridges are designed foruse in conjunction with reusable or other disposable syringe holders.Exemplary useful syringe holders are described, for example, in Hadtke,U.S. Pat. No. 4,585,445 and EPO 485,028 the disclosures of which arehereby incorporated by reference. Such a syringe holder 46 as depictedin FIG. 4, can comprise a cylindrical frame 48, a clamp 50, and aplunger element 52 containing a piston stem 58.

In preferred embodiments, the coupling system of this invention ispracticed in conjunction with a pre-slit injection site as described inPCT/US89/00273, PCT/US90/01350 and depicted in FIG. 2. Injection site 62has a cylindrical housing 64, a first end 66, a second end 68, and ahollow cylindrical fluid flow member 70 which can slidably engage areceiving member, e.g., the housing of a catheter, thereby providing asterile fluid flow coupling. Internal male luer threads 72, shown to becarried by housing 64 to adjacent the second end 68, engage a flangemember (not illustrated) when the injection site is rotated. Theinjection site 62 contains a resealable septum 74 formed of, forexample, a latex, synthetic rubber or thermoplastic elastomer. Theseptum 74 has either a partial or complete opening or slit 76.

The hub 20 preferably is attachable to the cartridge by snapping sleeveportion 22 over the distal end of the cartridge to engage the metal cap38. In order to obtain the requisite sterile seal and flexibility, thehub preferably is fabricated of a plastic material such as polyethyleneor polypropylene, or a polypropylene copolymer containing a minor amountof, e.g., low density polyethylene, to increase the impact strength ofthe polymer. An example of the latter copolymer is Pro-fax 8523,available from Himont Incorporated. Such copolymer is particularlypreferred when the hub is prepared by conventional injection moldingtechniques.

The hub 20 can be optionally provided with a first set of fins 54 at thebase of the blunt cannula for manufacturing purposes. Such fins may alsoprovide a sense of resistance alerting the user, to prevent the cannula16 and/or hub 20 from being penetrated too deeply into the port of aninjection site as shown in FIG. 2. The hub can optionally be providedwith a second set of fins 56 at the base of the sleeve to provide a stopfor the blunt cannula sheath.

The coupling system 10 of this invention can be prepared by inserting aneedle cannula 18 through the insert 24. The insert 24 is preferablyfabricated of an injection moldable plastic, e.g., polycarbonate orpolypropylene, and can be pre-sterilized or pre-treated for improvedadhesion, e.g., by corona discharge treatment. An adhesive, e.g., a UVcurable epoxy resin, can be applied to the needle/insert interface and,subsequently, the resin can be cured. The coupling system 10 preferablyis sterlizable such as by means of radiation, steam or ethylene oxide.The needle cannula-insert subassembly can then be press fit through thesleeve 22 into the hub 20. The sheath 28 can then be fitted over the hub20, and the coupling system-sheath subassembly can be snap fitted overthe necked down end of the cartridge 30.

In use, the coupling system 10 of this invention operates in conjunctionwith conventional medicament-containing cartridges, reusable syringeholders and injection sites during and after administration of aninjection as follows. In the injection state, the prefilled medicationcartridge 30 fitted with the coupling system 10 of this invention isloaded into cylindrical frame 48 of an assembled reusable syringe holder46 such as described above so that blunt cannula 16 covered by sheath 28extends distally outward from the frame. Cartridge 30 is then advancedby a health care worker distally through the holder by rotating clampingelement 50 until the inwardly extending proximal end of needle cannula12 penetrates sealed diaphragm 40 of cartridge 30.

Next, sheath 28 is removed to expose the outwardly extending distal endof blunt cannula 16. A screw threaded piston stem 58 is connected topiston 42 at the screw-threaded rod 44 thereof. The blunt cannula 16 isinserted into a pre-slit injection site, such as described above, and anaxially and distally directed force is applied by the health care workerto piston stem 52, via actuation button 60. The distal force istransferred from piston stem 58 to piston 44 to drive the piston throughmedicament-containing cartridge 30 and thereby expulse the fluidcontents of the cartridge 30 via needle cannula 18 through the fluidflow channel and into the fluid flow member 70 of the pre-slit injectionsite 62. After injection, the blunt cannula 16 is removed from theinjection site. Subsequently, the plunger rod 44 is unscrewed from thepiston thread and pulled proximally back, the clamp 50 is rotated tofree the cartridge 30 and the cartridge unit is disposed of in anappropriate manner, the needle cannula 18 being safely covered by thehub 20, sleeve 22 and/or blunt cannula 16 during the entire procedure,thus reducing the possibility of accidental needle strikes.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

What is claimed is:
 1. A coupling system-cartridge-syringe holderassembly comprising in combination,(1) a syringe holder comprising aframe, a clamp and a plunger element containing a piston stem; (2) acartridge loaded into the frame of said syringe holder, said cartridgecomprising a hollow body filled with a medication, a sealed diaphragm onthe distal end thereof and a piston axially and reciprocally slidablethrough the interior of said body; and (3) a coupling system fortransferring fluids from said cartridge to an injection site, saidcoupling system comprising:a fluid flow channel having proximal anddistal ends; a needle cannula defining the proximal end of said fluidflow channel; a hub attached to the distal end of said cartridgecomprising a blunt cannula portion defining the distal end of said fluidflow channel and a sleeve portion which extends beyond the proximal endof said needle cannula; wherein said cartridge can be advanced distallythrough said holder by rotating said clamp such that the proximal end ofsaid needle cannula penetrates said diaphragm, and said piston stem canbe connected to said piston and actuated to drive said piston throughsaid cartridge and expulse the fluid contents of said cartridge throughsaid fluid flow channel into an injection site.
 2. The couplingsystem-cartridge-syringe holder assembly of claim 1 wherein the sleeveportion of said hub has a radius of about 5 mm.
 3. The couplingsystem-cartridge-syringe holder assembly of claim 1 wherein the distancebetween the end of the sleeve and the proximal end of the needle cannulais at least 2 mm.
 4. The coupling system-cartridge-syringe holderassembly of claim 1 wherein said hub is fabricated of a plastic materialselected from the group consisting of polyethylene, polypropylene and apolypropylene copolymer containing low density polyethylene.
 5. Thecoupling system-cartridge-syringe holder assembly of claim 1 wherein thedistal end of said needle cannula is flush with the distal end of theblunt cannula.
 6. A coupling system-cartridge-syringe holder assemblycomprising in combination,(1) a syringe holder comprising a frame, aclamp and a plunger element containing a piston stem; (2) a cartridgeloaded into the frame of said syringe holder, said cartridge comprisinga hollow body filled with a medication, and a piston axially andreciprocally slidable through the interior of said body; and (3) acoupling system for transferring fluids from said cartridge to aninjection site, said coupling system comprising:a fluid flow channelhaving proximal and distal ends; a needle cannula defining the proximalend of said fluid flow channel; a hub attached to the distal end of saidcartridge comprising a blunt cannula portion defining the distal end ofsaid fluid flow channel and a sleeve portion; wherein said piston stemcan be connected to said piston and actuated to drive said pistonthrough said cartridge and expulse the fluid contents of said cartridgethrough said fluid flow channel into an injection site.
 7. A couplingsystem-cartridge-syringe holder assembly comprising in combination,(1) asyringe holder comprising a frame, a clamp and a plunger elementcontaining a piston stem; (2) a cartridge comprising a hollow bodyfilled with a medication and a piston axially and reciprocally slidablethrough the interior of said body; and (3) a coupling system fortransferring fluids from said cartridge to an injection site, saidcoupling system comprising:a fluid flow channel having proximal anddistal ends; a needle cannula defining the proximal end of said fluidflow channel; a hub attached to the distal end of said cartridgecomprising a blunt cannula portion defining the distal end of said fluidflow channel and a sleeve portion; wherein said piston stem can beconnected to said piston and actuated to drive said piston through saidcartridge and expulse the fluid contents of said cartridge through saidfluid flow channel into an injection site.
 8. A couplingsystem-cartridge-syringe holder assembly comprising in combination,(1) asyringe holder comprising a plunger element containing a piston stem;(2) a cartridge comprising a hollow body filled with a medication, asealed diaphragm on the distal end thereof and a piston axially andreciprocally slidable through the interior of said body; and (3) acoupling system for transferring fluids from said cartridge to aninjection site, said coupling system comprising:a fluid flow channelhaving proximal and distal ends; a needle cannula defining the proximalend of said fluid flow channel; a hub attached to the distal end of saidcartridge comprising a blunt cannula portion defining the distal end ofsaid fluid flow channel and a sleeve portion; wherein said piston stemcan be connected to said piston and actuated to drive said pistonthrough said cartridge and expulse the fluid contents of said cartridgethrough said fluid flow channel into an injection site.
 9. A couplingsystem-cartridge-syringe holder assembly comprising in combination,(1) asyringe holder comprising a plunger element containing a piston stem;(2) a cartridge comprising a hollow body filled with a medication, and apiston axially and reciprocally slidable through the interior of saidbody; and (3) a coupling system for transferring fluids from saidcartridge to an injection site, said coupling system comprising:a fluidflow channel having proximal and distal ends; a needle cannula definingthe proximal end of said fluid flow channel; a hub attached to thedistal end of said cartridge comprising a blunt cannula portion definingthe distal end of said fluid flow channel and a sleeve portion; whereinsaid piston stem can be connected to said piston and actuated to drivesaid piston through said cartridge and expulse the fluid contents ofsaid cartridge through said fluid flow channel into an injection site.